Jessica Oster

Assistant Professor
email: jessica.l.oster@vanderbilt.edu
Office: 6744 Science & Engineering Bldg
Phone: (615) 322-1461

Education

Ph.D. University of California, Davis, 2010
B.A. Oberlin College, 2003

Specializations

Paleoclimatology
Low Temperature Geochemistry
Cave and Karst Studies

General Interests

Jessica is interested in reconstructing the response of terrestrial hydroclimates to past climate change - including rapid climate transitions and long-term changes in mean climate. To do this, she develops records of isotopic and geochemical variability in terrestrial materials such as cave deposits (speleothems) and soil minerals. Speleothems and soil minerals capture the response of soil and groundwater to environmental changes on the surface, including changes in rainfall amount and source, temperature, and vegetation amount and type. These deposits are vital tools for investigating questions of global climate variability because they provide paleoclimate records in low and mid latitude terrestrial environments where other paleoclimate archives may be scarce. Jessica is also interested in understanding how modern cave systems respond to seasonal and interannual environmental changes with an eye toward using this understanding to provide an interpretative framework for calibrating paleoclimate records from cave deposits.

Current Research

I am also considering new M.S. and Ph.D. students for the Fall of 2012.

Jessica’s current research is focused on understanding how cave and soil minerals record environmental changes and using this knowledge to reconstruct past climate change in western North America. Jessica’s work is divided into three interrelated research areas.

1) Jessica is conducting detailed multi-proxy studies of speleothems from caves in the central and northern Sierra Nevada of California, in collaboration with scientists at the University of California, Davis and the Berkeley Geochronology Center. Comparison of oxygen, carbon, and strontium isotope variations and elemental concentrations in speleothem calcite reveals complex interactions between local hydrologic changes and climatic variability across Northern California during the Pleistocene and Holocene. This team is also working closely with climate modelers at NCAR and the University of Wisconsin to investigate potential driving mechanisms of regional precipitation variability in western North America during the last deglaciation.

2) Jessica is working with scientists at the USGS, UC Davis, and the Cave Research Foundation to investigate how modern cave environments in the Sierra Nevada respond to seasonal and interannual environmental variability, with the goal of using these observations to inform interpretations of speleothem geochemical records. Caves in the Sierra Nevada vary in size and hydrology and are developed across a wide range of elevation and latitude. Thus the environmental changes they experience, and their response to those changes, could vary substantially. There is still much to be understood about how water chemistry and air temperature, humidity, and pCO2 respond to environmental change in caves in California and the more arid portions of the western United States. Advancing this understanding is especially important given both the number of speleothem paleoclimate records being developed from this region and the potential for significant changes in water supply to this region due to future global climate change.

3) Jessica is working with scientists at Stanford University to investigate how changes in rainfall influence uranium isotope variations in soil silica and carbonate from the Great Basin of the western United States and silica speleothems from California. A solid understanding of how (234U/238U) varies in soil waters and minerals may allow the development of a widely applicable and robust proxy of rainfall variability. The combination of uranium isotope records with other paleoclimate proxy records from soil minerals could provide precisely dated reconstructions of variations in rainfall amount and source, and vegetation shifts in semi-arid regions across the globe.

Selected Publications

Oster, J.L., Montanez, I.P., Guilderson, T.P., Sharp, W.D. and Banner, J.L. 2010. Modeling speleothem δ13C variability in a central Sierra Nevada cave using 14C and 87Sr/86Sr, Geochimica et Cosmochimica Acta, v. 74, p. 5228 - 5242. doi:10.1016/j.gca.2010.06.030

Oster, J.L., Montanez, I.P., Sharp, W.D. and Cooper, K.M. 2009. Late Pleistocene California droughts during deglaciation and Arctic Warming: Earth and Planetary Science Letters, v. 288, p. 434 – 443. doi:10.1016/j.epsl.2009.10.003